1. Field of the Invention
The present invention relates to solid-state image pickup devices, driving methods for solid-state image pickup devices, and image pickup apparatuses, and more particularly, to an X-Y-address-type solid-state image pickup device that includes a pixel array area in which pixels each including a photoelectric conversion element are two-dimensionally arranged and that is capable of segmenting and reading pixel information in a desired region of the pixel array area, to a driving method for the solid-state image pickup device, and to an image pickup apparatus using the solid-state image pickup device as an image pickup device.
2. Description of the Related Art
X-Y-address-type solid-state image pickup devices typified by complementary metal oxide semiconductor (CMOS) image sensors are capable of selecting pixels row by row, column by column, or pixel by pixel in a pixel array area in which pixels each including a photoelectric conversion element are two-dimensionally arranged. Thus, such X-Y-address-type solid-state image pickup devices are capable of segmenting and reading pixel information in a desired region of the pixel array area by designating the desired region. (See, for example, Japanese Unexamined Patent Application Publication No. 2001-45383.)
A CMOS image sensor that is capable of segmenting and reading pixel information in a desired region of a pixel array area is shown in FIG. 11 of Japanese Unexamined Patent Application Publication No. 2001-45383.
Referring to FIG. 11, in a pixel array area 101, pixels (not shown) each including a photoelectric conversion element are two-dimensionally arranged. The pixel array area 101 includes an effective pixel region 102, a light-shielded pixel region 103, and a partial-read region 104. In the effective pixel region 102, image light from an object is incident to each pixel, and a signal obtained by photoelectrically converting the image light at the pixel is used as an image pickup signal. The light-shielded pixel region 103 is disposed around the effective pixel region 102. Each pixel in the light-shielded pixel region 103 is light-shielded, and a signal of the pixel is used for determining a black level. The partial-read region 104 is a desired region that is externally set.
A row read control circuit 105, a row reset control circuit 106, a parallel signal processing circuit 107, an output control circuit 108, and an amplifying circuit 109 are disposed around the pixel array area 101. The row read control circuit 105 controls row reading of pixels corresponding to reading of a desired row range. The row reset control circuit 106 resets electric charges stored by photoelectric conversion at pixels in different rows, at the same time as row reading, to control a storage time of the electric charges to realize electronic shuttering (similarly to the row read control circuit 105, the operation of the row reset control circuit 106 corresponds to reading of the desired row range). The parallel signal processing circuit 107 performs noise removal, signal processing, A/D conversion, and the like for signals, in parallel, read from pixels in units of rows. The output control circuit 108 controls sequential outputs of the parallel signal processing circuit 107, and the operation of the output control circuit 108 corresponds to reading of a desired column range. The amplifying circuit 109 amplifies outputs of the parallel signal processing circuit 107 and outputs the amplified results to the outside. A timing control circuit 110 performs timing control corresponding to desired operation modes for the circuits.
In the known CMOS image sensor, when pixel information in the desired partial-read region 104 is sequentially read row by row, access control for reading and the like is not performed for pixels in rows below and above the partial-read region 104. Thus, electric charges photoelectrically converted and stored at a photoelectric conversion element in each of the pixels may exceed the storage capacity of the photoelectric conversion element and may leak to peripheral pixels. The electric charges that leak to the peripheral pixels affect image pickup in the peripheral pixels. In the known CMOS image sensor, when electric charges leak from pixels above and below the partial-read region 104 to pixels in the partial-read region 104, an abnormal image (generally, a brighter or whiter image) is acquired in the region to which the electric charges leak. This is a well-known phenomenon generally called “blooming”.